Closing the box: do you only get 1 shot at it?

[nkwak]

I recently attempted to close the box on my first build and at the time everything seemed to fit flush. I don't have humidity control in my shop but things were pretty stable in the mid to upper 30th percentile (36%-39%) while the glue cured. When I took it out of the go bar deck though, I discovered that a portion of the top did not glue down because things did not fit quite right. Is it too late to get in there and sand or chip away at things? When it comes time to re-glue the rims do I need to remove the previously cured but unbonded Titebond in order to get a good glue joint?

[kencierp]

Yes you need to get down to bare wood for re-gluing, a rotor wire brush in a Dremel tool works good --- there is a chemical available that removes PVA glue "D-Glu Gone" ? or something like that -- perhaps one of the other members remembers the name of the product. I've never used it but would certainly give it a try on a large repair job like the one you have ahead of you.

[Darryl Young]

Yes, it's called D-Glue-Goo.....and it works well. I'm not sure it will get between the rim and your top as it only works where it's in contact with the glue. Maybe Rick Davis will chime in.

What kind of glue did you use?

[Ben-Had]

How much remains unglued? Once you clean the glue out, dry clamp it and see if there looks to be any issues, if not, work some glue into the joint with a palette knife and re-glue it.

[Jim_H]

I just glued the back on one of my Dread prototypes.

I went through 3 or 4 dry runs, checking for fit and gaps. I used a thin feeler guage (you can use a piece of bond paper too) to make sure there were no gaps, especially on either side of each of the braces. I didn't reach for the glue bottle until I had a good tight fit all the way around.

I also pre-stage all of the clamps I'll be using (or go bars and cauls if that is your preference), so that you can get everything clamped down.

You have to move fairly quickly getting the glue bead down and everything in place before the glue starts to dry on you. If you put the glue on too thin it can skin and dry pretty fast. If you use too much you end up with a big mess to clean up (difficult to impossible once the box is closed).

De-Glue Goo is cheap and can be found at most craft stores and at wood craft. It will dissolve any water based glue in a minute or two, but you'll probably need to pull the back off to get everything cleaned up property, and re-assess your fit. Heat from a household iron along with a spatula or putty knife should do the job. Just be careful not to damage the rim or your back set with the knife.

[nkwak]

Thanks, but I don't know if I'm following. Do I need to steam the top completely off? Essentially, the only unglued areas are around the upper transverse brace on the upper left (bass side) bout and about 2"-3" at the waist on the same side. The gap is not that great; I can fit a piece of sand paper through it.

How viscous is this De-Glue Goo? Will it seep into other joints? Should I be concerned about it dissolving the glue holding the kerfing on?

FWIW I used Titebond for everything so far (apart from CA for the rosette) and I didn't put a whole lot when I glued it up so there was no squeeze out whatsoever. That concerns me as well.

[Ben-Had]

How much remains unglued? Once you clean the glue out, dry clamp it and see if there looks to be any issues, if not, work some glue into the joint with a palette knife and re-glue it.

Once again and this id just me, I'd treat it like a repair. Generally NOT going to remove the top of a guitar, mandolin, fiddle, etc. if the is a seam separation at the top/side. Clean it, check it, glue it.

[Jim_H]

Thanks, but I don't know if I'm following. Do I need to steam the top completely off? Essentially, the only unglued areas are around the upper transverse brace on the upper left (bass side) bout and about 2"-3" at the waist on the same side. The gap is not that great; I can fit a piece of sand paper through it.

How viscous is this De-Glue Goo? Will it seep into other joints? Should I be concerned about it dissolving the glue holding the kerfing on?

FWIW I used Titebond for everything so far (apart from CA for the rosette) and I didn't put a whole lot when I glued it up so there was no squeeze out whatsoever. That concerns me as well.

It's hard to say. Based on what you've said so far, I would probably remove it, unless you think you'll cause more harm doing so. Removing it should just be a matter of taking a household iron and heating up a section until it releases, and working your way around. Once you get it off, you can clean it up with de-glue goo. To me, this is the only way to be sure you've got all of the old glue removed and can get back to getting a good tight joint. Running sandpaper through the crack seems like a good way to compromise the fit even more (if you remove wood along with the glue).

De-Glue Goo is a clear gel, about the same consistency as white glue. It won't penetrate deeply into a joint to open it up. It's more for cleaning up surface glue, smears, etc.. You'll need to use heat to remove the back if you choose to go that route.

[Darryl Young]

Can you clamp the gap shut or has the glue setup holding the gap apart? Either situation concerns me (for different reasons) but if you can't close the gap without breaking the glue bond (or cracking wood somewhere) you have no choice but to remove the top (or back, whichever it was), cleanup all the glue, make sure you have a good fit around the perimeter, and re-glue.

You might have other options with fish glue or HHG.

[tippie53]

I can't count how many clamps I use on a top , but I do clean off the rack. You can never have too many clamps or dry fit too often . If you do use a go bar . make yourself a HALO pattern that sits on above the rim , that way you can distribute the force of the go bars better .
Learning the best clamping procedures can be tricky. I had a press for this job but someone came to my shop and made me a crazy offer . I love the way Martin is doing them now with an air bag. Guess what I am going to make.